Programmable logic controls (PLCs), where control programs are placed in a program memory as a sequence of instructions, are regularly used in automation technology as plant and operation centre controls. A PLC can have a control device solely intended for control purposes, which can be adapted to specific control functions by reading a specific control program into the program memory. Alternatively PLCs can also be implemented with a universal computer, such as a standard personal computer, on which runs the corresponding control program (soft PLC), which leads to a cost savings due to the omission of specific hardware components. In addition, when using a soft PLC more flexible program logics can be programmed, so that the use of soft PLCs in many sectors of automation technology nowadays constitutes a standard with which in a cost-effective, efficient manner it is possible to implement a flexible control of complex plants and the possibility of providing a comfortable operating surface compared with a conventional PLC contributing to this.
However, more particularly in complex, multilayer automation processes, the use of flexible programmable logic controls gives rise to various technical problems, e.g. in connection with fault finding in the actual plant and also in the PLC program, in the optimization of production sequences and in conjunction with subsequent, flexible interrogations (characteristic data generation for testing or training purposes), which are not or are only inadequately solved in the known PLC-controlled plants.
On the basis of the above-described, prior art problems and disadvantages, the problem of the invention is to further develop an electronic plant control method and apparatus in such a way that they can be flexibly used for process analysis, plant simulation, fault finding and optimization, as well as for training purposes and preventative plant maintenance.